With the known technology, whether an opening-closing member entraps an external object when the opening-closing member is moved from an open state to a closed state is detected and the movement of the opening-closing member is reversed when it is judged that the external object is entrapped. In order to achieve the foregoing, it is required to detect the entrapment of the external object by the opening-closing member.
Japanese Patent Laid-Open Publication No. H09-264094 describes a device including a sensor provided along an end surface of the opening-closing member. A conduction portion of the sensor is covered with a rubber. When the sensor detects ON state, the device described in Japanese Patent Laid-Open Publication No. H09-264094 detects the entrapment of the external object between the sensor and a vehicle body.
Japanese Patent Laid-Open Publication No. 2000-160931 describes a device for detecting the entrapment of the external object based on a variation of a rotational speed of an electric motor and a variation of an electric current supplied to the electric motor for actuating the opening-closing member.
Notwithstanding, because the detection of the entrapment using the sensor only detects the entrapment at a location provided with the sensor, the entrapment of the external object cannot be detected when the external object is entrapped without contacting the sensor.
In the meantime, with the detection for the entrapment of the external object based on the variation of the rotation speed of the electric motor, because, generally, various members such as a cable and a decelerator are provided between the electric motor and the opening-closing member, a time lag may be generated from the entrapment of the external object until the rotational speed of the electric motor is actually changed. Thus, the timing for detecting the entrapment of the external object after actual entrapment may be delayed.
A need thus exists for a detecting device for an opening-closing member for securely detecting the entrapment of an external object and minimizing the delay of the detection timing.